There are a number of specific medical therapies available to patients with primary immunodeficiency diseases. They have made the effective therapy of these disorders a reality for most patients, improving their quality of life and allowing them to become productive members of society. Three established therapies are: gamma globulin replacement, bone marrow transplantation, and gamma interferon therapy. Their specific indications and the disorders for which they may be of benefit should be discussed with your physician.
The term, gamma globulin, refers to the fraction of blood plasma that contains immunoglobulins or antibodies. Individuals who are unable to produce adequate amounts of immunoglobulins or antibodies, such as patients with X-Linked Agammaglobulinemia, Common Variable Immunodeficiency, or other forms of hypogammaglobulinemia, may benefit from replacement therapy with gamma globulin. The gamma globulin temporarily replaces the missing antibodies and prevents infections. Unfortunately, approximately 1/2 of the infused gamma globulin containing the antibodies is eliminated over 3 to 4 weeks, so that patients must be infused every few weeks in order to maintain adequate levels.
Transplantation of stem cells from a normal donor to an immunodeficient recipient is a highly specialized procedure that can be used to treat some primary immunodeficiency diseases. Traditionally, stem cells were obtained from bone marrow, but now peripheral blood and blood obtained from the placenta at birth (cord blood) are excellent alternatives. The primary immunodeficiency diseases for which bone marrow transplantation is most commonly performed include those diseases that are characterized by deficient T-lymphocytes or combined deficiencies of T-lymphocytes and B-lymphocytes. Bone marrow transplantation is most often used to treat Severe Combined Immunodeficiency (SCID). Bone marrow transplantation has also been used in some patients to treat other primary immunodeficiency diseases such as the Wiskott-Aldrich syndrome, X-linked Hyper-IgM Syndrome, and Chronic Granulomatous Disease.
The transplantation of bone marrow from a normal individual to an immunodeficient individual has the potential to replace the deficient immune system of the patient with a normal immune system. However, there are two problems in performing a bone marrow or stem cell transplant.
The first problem is the fact that except for the children with the most complete form of Severe Combined Immune Deficiency, all patients (the recipient, or host) will have enough immune function remaining to cause them to recognize the transplanted marrow as foreign, react against it and reject it. This first problem is called graft rejection. Thus, most patients must be treated with chemotherapy and/or radiation therapy in order to prevent them from rejecting the transplanted marrow. Although the chemotherapy and/or radiation therapy prevents the patient (recipient) from rejecting the transplanted marrow, it may cause serious side effects. These include loss of all of the cells of the bone marrow, including the red cells that carry oxygen, the white cells that help fight infection, and the platelets that help the blood clot. In fact, there is a very high risk of contracting a serious infection during the weeks immediately after a transplant.
The chemotherapy also may cause severe blistering of the mouth or other mucus membranes that makes eating and drinking impossible. It is because of these serious complications that transplantation is reserved for those patients with the most severe immune defects.
The second problem is the fact that the transplanted bone marrow (or graft) carries the immune system of the donor and may therefore recognize the patient (or recipient or host) as foreign, react against the patient and attack the patient. This second problem is called graft vs. host disease (GvHD).
Phagocytic cells (neutrophils, monocytes, eosinophils) of patients with Chronic Granulomatous Disease of childhood (CGD) do not kill some types of bacteria and fungi (see chapter on Chronic
Granulomatous Disease). An international study with gamma interferon has shown that CGD patients who are given gamma interferon three times weekly subcutaneously had approximately 70% fewer serious infections than did those patients not receiving gamma interferon. Also, when those patients taking gamma interferon have infection they require less time in the hospital. Benefit from gamma interferon is most evident in children under 10 years of age, but all age groups benefit. Gamma interferon is supplied in a single dose vial of 0.5 ml. The dose for each patient is determined by body surface area, which means that both height and weight are considered. For small children, the surface area is not a reliable method, so they are dosed by weight alone. The vials must be kept refrigerated, never frozen, and should not be shaken. There is no preservative in the gamma interferon preparation, so opened vials should be discarded after 12 hours at room temperature. Expired vials should not be used. Gamma interferon is given as a subcutaneous injection three times a week (such as Monday, Wednesday, and Friday). The preferred sites for injection are the right and left thigh and arm. Administration is similar to giving insulin to diabetics. Used syringes should be disposed of in an approved needle waste box and the full box returned to the physician or local emergency room for proper incineration. Never discard needles and syringes in your household trash.